Syntheses, crystal structures and photocatalytic properties of transition metal complexes based on 9,10-anthraquinone-1,3-dicarboxylate

Abstract

Five transition metal complexes based on the ligand 9,10-anthraquinone-1,3-dicarboxylate acid (1,3-H2AQDC) have been synthesized and characterized by physico-chemical and spectroscopic methods. Single-crystal analyses show that the complexes {Mn(1,3-AQDC)(H2O)4·(H2O)}n, {Zn(1,3-AQDC)(H2O)4·(H2O)}n, {Ni(1,3-AQDC)(4,4′-bpy)(H2O)2(CH3OH)}n and {Co(1,3-AQDC)(4,4′-bpy)(H2O)2(CH3OH)}n (4,4′-bpy = 4,4′-bipyridine) comprise one-dimensional (1D) chains in their crystal structures, while [Ni(1,3-AQDC)(H2O)4·(H2O)3]2 bears dimeric units, and these secondary building units are further linked by hydrogen bonding to form three-dimensional structures. These compounds proved to be able to catalyze visible-light-driven air-oxidation reactions of diarylethyne into diketones under mild conditions.